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The typical question customers ask when purchasing a new projector for the home, office, or classroom is: should I get an LCD projector or a DLP projector? LCD, an acronym for ‘liquid crystal device’ and DLP, an acronym for ‘digital light processing’ are the two most common projector imaging technologies. With so many different brands and models available, it can be challenging for customers to pick between the two technologies. It comes down to the fact that LCD projectors offer superior image quality and colour accuracy. The article below explains why DLP projectors struggle with creating a similar standard of image quality.

It’s like a set of blinds in your room for your bedroom window. By twisting a rod you can have the shutters open or closed, according to if you want to let light in or not. That is exactly how an LCD projector functions. Each pixel works like a single shutter on a set of blinds to either allow light through or to block it. DLP on the other hand is created of millions of microscopic mirrors or ‘pixel elements’ as experts like to call them. Each pixel element works to either reflect light or block it.

How the light source is processed from when the projector is switched on to when the content reaches your screen is vitally important in regard to image quality, brightness and colour accuracy. LCD projectors direct white light from the lamp by dividing it into red, blue and green components, by three mirrors which project the coloured light to 3 stand alone LCD panels. The 3 LCD panels cast the elements of the image by switching each pixel on and off. The pixels are then projected in a glass prism to deliver the projector image. Something to realise about LCD projectors is that all three colours are sent onto your screen simultaneously. The way a DLP projector runs is widely different and even the produced image appears is not the same. With DLP, white light from the lamp is directed through a spinning colour wheel with transparent red, blue and green segments, at speeds up to 11,000 rpm/s. This approach to making an image casts a sequence of red, blue and green light. The millions of micro mirrors as described above reflect the coloured light on the pixels to produce the image elements. The elements of the image are displayed in sequence on the screen, one colour at a time. The viewer’s eyes will then put together each coloured element of the image into a single total image. In LCD projectors, all colours are available all the time to offer the top level of brightness and great colour accuracy. In DLP, just one colour is available at a time, resulting in lower colour brightness and accuracy. Some designers have placed a white segment into the colour wheel to improve overall brightness, but this further damages colour accuracy.

I find in forums all the time that DLP has a higher contrast ratio and therefore must be superior. For those unaware, the contrast ratio is a measure of a display system defined as the ratio of the luminance of the brightest white to that of the darkest black that the technology is capable of. DLP projectors do have high contrast specifications when compared to the majority of LCD projectors. At a glance, this seems to be a benefit, however, in the real world, the true black level is determined by the ambient light in the room when the projector is being utilised. Do not be hoodwinked by contrast specifications on websites and in brochures.

When the content you are trying to see needs moving images, DLP projection technology can also create image imperfections, or ‘artifacts’. The most typical artifact that a DLP projector displays with moving images is colour break up. Colour break up is unavoidable in DLP systems because moving images change between the time red, blue and green colours are displayed. LCD projectors do not have this characteristic because all colours are projected at once. DLP manufacturers have developed 3DLP solutions using 3 chips to solve the colour break up issue, but the cost of these projectors make them almost impossible for most businesses and consumers.

Another differentiation between LCD and DLP is how they make up for the refractive qualities of light. Take yourself back to high school science, and recall when they taught you how various colours of light refract various amounts when projected through the same lens. The disadvantage with DLP projectors is that they utilise the one same panel with the same lens to project Red, Blue and Green. All 3 colours are different and refract light at different levels. Most of the time with a DLP projector, a spill of yellow colour will be projected above and a spill of blue will show below an image containing something as simple as a lone black line. While being built LCD projectors can be set to remove these effects on the projected image, as each colour is directed on isolated LCD panels.

The isolated real benefit (excluding price) with deciding on a DLP projector is its overall smaller size and weight. However, this is only relevant with regard to transport and needs to be traded off against the image advantages of LCD projectors. If resulting picture quality is important to you, then the decision is simple. Go for an LCD projector! LCD projectors will constantly make bright, colourful images with fewer image blips. If you desire to ask more about LCD technology in more detail, have a look at this spectacular resource website: Explore 3LCD. If you have any additional questions, visit Projector Central and send me an email.

Jonathan King is the sales and marketing manager of Projector Central, Australia’s leading online shop for projectors. Based in Brisbane, Projector Central has serviced Australia for 15 years. For data projectors in the Gold Coast and Interactive Whiteboards, contact Projector Central today.

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